Lutetium Phthalocyanine Research Articles

Looking for the optimal harvest time of red grapes with an enzymatic electrochemical multisensory system

The timing of the grape harvest is a critical decision for winemakers, as it greatly impacts the quality and organoleptic characteristics of the resulting red wines. One key indicator for determining the optimal harvest time is the phenolic content of the grapes. As the berries ripen, phenolic compounds in the grape skin cells migrate from the seeds to the pulp and finally to the skin. However, monitoring these phenolic changes, particularly in the seeds, presents a challenge. This research addresses this problem by developing a novel technique to track the phenolic composition of seeds during ripening. The objective is to provide a reliable method for winemakers to monitor the phenolic evolution and improve harvest decision-making.In this study, a multisensory system consisting of four electrochemical enzymatic carbon paste sensors, modified with tyrosinase and electrocatalytic materials (AuNPs, lutetium phthalocyanine, and nickel oxide nanoparticles), was employed to analyze the phenolic content in grape seed extracts. The system monitored weekly changes in the phenolic composition of the seeds from three red grape varieties—Cabernet Sauvignon, Tempranillo, and Prieto Picudo—during their ripening from veraison to being overripe. Using voltammetric techniques, the electrochemical responses were characterized by shifts in peak positions and intensity changes, reflecting the oxidation/reduction of phenols. Principal Component Analysis (PCA) demonstrated the ability of the array of sensors to discriminate phenolic changes across ripening stages, while Partial Least Squares (PLS) regression provided robust correlation models between the electrochemical responses and seed phenolic content, with correlation coefficients ranging from 0.93 to 0.99. The developed methodology successfully tracked phenolic changes, offering a promising tool for monitoring grape seed maturation and assisting in determining the optimal harvest time.

Iodinated lutetium (III) phthalocyanine: Synthesis, photochemical and nonlinear optical properties

New octaiodo-substituted lutetium (III) phthalocyanine was prepared using a six-step synthetic procedure starting from commercially available o-xylene. The amide synthesis and dehydration step were optimized. The influence of the nature of peripheral halogen atoms on optical and photochemical properties was studied. For the complex under study, the possibility of participation in photoreactions of types I and II with the formation of two different forms of reactive oxygen species was investigated: superoxide anion radical and singlet oxygen respectively. Competition between two photoreactions was demonstrated. The Z-scan method revealed a pronounced nonlinear optical response of the iodinated complex, caused by the action of heavy atoms of peripheral iodine groups.

Novel non-peripheral mercaptopyridine-substituted mono- and double-decker lutetium(III) phthalocyanines: synthesis, photophysicochemical and electrochemical properties.

In this study, novel non-peripheral tetra-mercaptopyridine-substituted mono- and double-decker phthalocyanines (LuPc and LuPc2) containing lutetium(III) as a rare earth metal were synthesized and characterized using different spectroscopic techniques. ESR and electrochemical analyses were performed to support the sandwich structure of LuPc2. The g factor was determined to be 2.00039 and the characteristic first reduction couple at 0.29 V indicated a reduction of the radical Pc ring of LuPc2. In addition, the UV-Vis-NIR spectra of LuPc2 in neutral, reduced, and oxidized states demonstrate its intrinsic π-radical nature in CHCl3. The photophysicochemical properties of LuPc and LuPc2 were investigated in DMSO. It was found that mono-phthalocyanine (LuPc) is a more effective photosensitizer than double-decker (LuPc2) and metal-free (H2Pc) phthalocyanines based on a comparison of their photophysical and photochemical properties. The singlet oxygen quantum yields (ΦΔ) of the synthesized LuPc and LuPc2 compounds were calculated to be 0.57 and 0.14, respectively, and the obtained results were compared with H2Pc (ΦΔ = 0.04). Also, electrochemical measurements were performed to estimate their redox potentials and the results indicated the important electrochemical performance of double-decker phthalocyanine (LuPc2).

Sonophotochemical and photochemical efficiency of thiazole-containing metal phthalocyanines and their gold nanoconjugates.

This study presents the synthesis of some metal {M = Zn(II), Lu(III), Si(IV)} phthalocyanines bearing chlorine and 2-(4-methylthiazol-5-yl) ethoxy groups at peripheral or axial positions. The newly synthesized metal phthalocyanines were characterized by applying FT-IR, 1H NMR, mass, and UV-Vis spectroscopic approaches. Additionally, the surface of gold nanoparticles was modified with zinc(II) and silicon(IV) phthalocyanines. The resultant nanoconjugates were characterized using TEM images. Moreover, the effect of metal ions and position of substituent, and gold nanoparticles on the photochemical and sonophotochemical properties of the studied phthalocyanines was investigated. The highest singlet oxygen quantum yield was obtained for the lutetium phthalocyanine by applying photochemical and sonophotochemical methods. However, the linkage of the zinc(II) and silicon(IV) phthalocyanines to the surface of gold nanoparticles improved significantly their singlet oxygen generation capacities.

PDT and PD of Human Glioblastoma with 5-ALA/PpIX and n-GalLuPc

Glioblastoma (GBM) is the most common and severe type of brain tumor. Surgery and subsequent radiotherapy and chemotherapy do not lead to sufficient results in the treatment of this type of malignancy, mostly due to its specific morphology. Only about 6% of the patients of advanced age survive 5 years after being diagnosed with GBM. Therefore, scientists are working on alternative therapies that would lead to more effective and long-term treatment of glioblastoma. Photodynamic therapy (PDT) and photodiagnostics (PD) are such unconventional methods for treating and diagnosing malignant tumors. During our work, more than 20 experiments were carried out with stem cells cultivated from human glioblastoma tumors. We used two types of photosensitizers – delta-aminolevulinic acid (5-ALA) as a precursor of protoporphyrin IX (PpIX) and non-peripherally galactosylated lutetium phthalocyanine (n-GalLuPc). After the irradiation supernatant samples of photosensitizer-treated cell lines were used for evaluation of photosensitizers’ accumulation in the cell lines investigated. The emitting spectra is correlated with the total induced cell death in the treated cells. After considering the overall effectiveness of the two photosensitizers, n-GalLuPc showed higher efficiency. These in vitro results prompted the future investigation of the phthalocyanine for in vivo application in GBM treatments.

Biological properties of hexadeca-substituted metal phthalocyanines bearing different functional groups

In this study, a new tetra-substituted phthalonitrile (diethyl 2-(2-chloro-4,5-dicyano-3,6-bis(hexyloxy)phenyl)malonate) bearing three different substituents was synthesized and characterized. Due to the basic medium, transesterification occurred during the synthesis of the target phthalocyanines [M = Zn (II), Cu (II), Co (II), In (III), Lu (III)] in n-pentanol and the ethyl groups were replaced with pentyl groups. The biological features of the resultant compounds were studied for the first time in this study. All the compounds exhibited high antioxidant, antimicrobial, and DNA cleavage activities. The highest antioxidant activity was obtained 90.39% for lutetium phthalocyanine at 100 mg/L. The most effective MIC value was obtained 8 mg/L against Candida parapisilosis. The most effective microbial cell viability inhibition was obtained 100% for cobalt and lutetium phthalocyanines. They exhibited excellent biofilm inhibiton activities. Higher biofilm inhibition was achieved using light irradiation. The compounds exhibited higher biofilm inhibition activities with photodynamic against Staphylococcus aureus compared with Pseudo aureginosa.

Dark and photoinduced cytotoxicity of solubilized hydrophobic octa-and hexadecachloro-substituted lutetium(III) phthalocyanines

Chloro-substituted lutetium(III) phthalocyanines were obtained using fast and effective (yields 75–78%) template synthesis under microwave irradiation. Target compounds possess intense (logε ∼ 5) absorption in the range 680–700 nm, which overlaps with the “therapeutic window” range for photosensitizers in photodynamic therapy. Chloro-substituted complexes demonstrate moderate quantum yields (up to 54% for perchlorinated complex) of singlet oxygen generation. Moreover, chloro-substituted lutetium(III) phthalocyanines showed the ability to generate the superoxide anion radical (O2–•) with higher efficiency compared to unsubstituted analog. Stable colloid suspensions of the water-soluble nanoparticles were obtained by incorporation of the chlorinated lutetium(III) phthalocyanines into mixed polylactide micelles. The dark and photoinduced cytotoxic activity of the obtained nanoparticles was tested using the HeLa cell line. Demonstrated results showed a promising potential of the chlorinated lutetium(III) phthalocyanines as photosensitizers for medical applications.

Tetra- and octasubstituted lutetium bisphthalocyanines with (trioxyethylene)thia and (trioxyethylene)oxy groups: Electrochemical and sensor properties

In this study, tetra- and octasubstituted lutetium bisphthalocyanines (LuPc2) bearing (trioxyethylene)thia- and (trioxyethylene)oxy-moieties were synthesized and characterized. The effect of the heteroatom (S or O) and the number of substituents in phthalocyanine macrocycles on their electrochemical properties and sensor response to ammonia was investigated. The films of all investigated LuPc2 derivatives demonstrated reversible chemiresistive sensor response to ammonia (0.1–30 ppm) at room temperature. It was shown that the films of octasubstituted lutetium bisphthalocyanines exhibited the higher chemiresistive sensor response to ammonia compared to tetrasubstituted ones. In turn, phthalocyanines bearing (trioxyethylene)oxy-substituents had the higher sensor response compared to those with (trioxyethylene)thia-moieties. These results were correlated with the decrease in the value of ΔE1/2 obtained as a result of electrochemical studies. ATR FT-IR spectroscopy was used to study the nature of interactions between ammonia and the lutetium phthalocyanine molecules.

Double-decker lutetium phthalocyanine functionalized with 4-phenylthiazol-2-thiol moieties: Synthesis, characterization, electrochemistry, spectroelectrochemistry and electrochromism

In this study, the synthesis, spectral characterization, electrochemistry, spectroelectrochemistry and electrochromism of a novel double-decker lutetium phthalocyanine, bis-[2(3),9(10),16(17),23(24)-tetrakis-[2-(4-phenyl-2-thiazolyl)sulfanyl] phthalocyaninatolutetium(III), denoted as LuPc2, is reported. The LuPc2 synthesized in this study is unique, being the first thiazole-containing double-decker lutetium phthalocyanine complex published to date. The electrochemistry of LuPc2 was used to support the proposed sandwich structure. A characteristic first reduction couple at 0.32 V indicated reduction of the radical Pc ring of LuPc2. The other redox process indicated electron transfer reactions of each Pc ring, which is in harmony with other sandwich type Pc complexes. Distinct color changes of LuPc2 in solution showed its possible use in the solid state as an electrochromic material; thus, the electrochromic responses were analyzed using a LuPc2 film. Fast, stable and reversible electrochromic responses were observed with green to red color changes.

Comparatively singlet oxygen efficiency by sono-photochemical and photochemical studies of new lutetium (III) phthalocyanines

This study performs a sono-photochemical method to get more effective therapeutic outcomes for cancer treatment. Additionally, sonochemical and sono-photochemical properties of lutetium phthalocyanines have been presented in this study for the first time. Although it aims to synthesize a series of new peripherally/non-peripherally mono lutetium (III) phthalocyanines (1-3Lu), the related double-decker lutetium (III) phthalocyanines (1′-3′Lu) were simultaneously synthesized. Characterization of the resulting macromolecules was carried out using diverse spectroscopic approaches including NMR (1H and 13C NMR; for 1-3Lu), UV–Vis, FT-IR, and Mass spectroscopy. The double-decker lutetium (III) phthalocyanines (1′-3′Lu) were also characterized by performing electron spin resonance (ESR) measurements. The solubility of all the new macromolecules was studied using different polar and non-polar organic solvents. The photophysicochemical properties of the resulting mono lutetium (III) complexes were analyzed and photochemical, sonochemical, and sono-photochemical properties were investigated to determine the efficiencies of singlet oxygen. When the data were compared, the highest singlet oxygen quantum yields (ΦΔ = 0.86 for 1-Lu, 0.96 for 2-Lu, 0.83 for 3-Lu) were obtained for the sono-photochemical studies. The results prove that sono-photochemical properties improve the therapeutic effects compared to photochemical ones.

Novel lutetium(III) phthalocyanine-coumarin dyads; synthesis, characterization, photochemical, theoretical and antioxidant properties

In this study, novel 7-oxy-3-ethyl-6-hexyl-4-methylcoumarin substituted lutetium(III) phthalocyanine compounds were synthesized, characterized and their photochemical, theoretical, and antioxidant properties were examined. All complexes were characterized by common spectroscopic methods such as FT-IR, UV–vis, 1H NMR, MALDI-TOF-MS and elemental analysis as well. Geometry optimization of phthalocyanine compounds was calculated in the B3LYP functional using 6-31G (d, p) + SDD basis set of the Density Functional Theory. Aggregation, singlet oxygen generation, and photodegradation behavior under light irradiation of the complexes (1–4) were investigated in dimethylformamide. The three phthalocyanine compounds (1, 2, and 4) showed a high level of singlet oxygen efficiency were compared with the unsubstituted zinc(II) and lutetium(III) phthalocyanine compounds because their quantum yield values were found to be over 0.80. The radical cation scavenging activities of the compounds 3 (120.344 mM trolox/mg) and 4 (188.733 mM trolox/mg) are quite remarkable in 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid analysis according to butylated hydroxyanisole (52.63 mM trolox/mg).

Grafting, self-organization and reactivity of double-decker rare-earth phthalocyanine

Unveiling the interplay of semiconducting organic molecules with their environment, such as inorganic materials or atmospheric gas, is the first step to designing hybrid devices with tailored optical, electronic or magnetic properties. The present article focuses on a double-decker lutetium phthalocyanine known as an intrinsic semiconducting molecule, holding a Lu ion in its center, sandwiched between two phthalocyanine rings. Carrying out experimental investigations by means of electron spectroscopies, X-ray diffraction and scanning probe microscopies together with advanced ab initio computations, allows us to unveil how this molecule interacts with weakly or highly reactive surfaces. Our studies reveal that a molecule–surface interaction is evidenced when molecules are deposited on bare silicon or on gold surfaces together with a charge transferred from the substrate to the molecule, affecting to a higher extent the lower ring of the molecule. A new packing of the molecules on gold surfaces is proposed: an eclipse configuration in which molecules are flat and parallel to the surface, even for thick films of several hundreds of nanometers. Surprisingly, a robust tolerance of the double-decker phthalocyanine toward oxygen molecules is demonstrated, leading to weak chemisorption of oxygen below 100 K.

New Quadratic Self-Assembly of Double-Decker Phthalocyanine on Gold(111) Surface: From Macroscopic to Microscopic Scale

Unveiling the self-organization mechanism of semiconducting organic molecules onto metallic surfaces is the first step to design hybrid devices in which the self-assembling is exploited to tailor magnetic properties. In this study, double-decker rare-earth phthalocyanines, namely, lutetium phthalocyanine (LuPc2), are deposited on Au(111) gold surface forming large-scale self-assemblies. Global and local experimental techniques, namely, grazing incidence X-ray diffraction and scanning tunneling microscopy, supplemented by density functional theory calculations with van der Waals corrections, give insight into the molecular structural arrangement of the thin film and the self-organization at the surface. Our results show unambiguously that the two plateaus of the double-decker phthalocyanine present a different rotation than the isolated molecule. This is evidenced by density functional theory simulations of optimized LuPc2 monolayer showing a perfect agreement with experimental findings. Moreover, the stabilized structure of double layers reveals an eclipsed configuration of the molecules in the stacking, having the ligand plateaus parallel to the gold surface. The high crystallinity of the molecular assembly and its weak electronic coupling with the metallic substrate is expected to open new perspective in the design of optoelectronic or magnetic devices.

A Spin-Active, Electrochromic, Solvent-Free Molecular Liquid Based on Double-Decker Lutetium Phthalocyanine Bearing Long Branched Alkyl Chains.

Synthesis and characterization of a novel, multifunctional, solvent-free room-temperature liquid based on alkylated double-decker lutetium(III) phthalocyanine (Pc2 Lu) are described. Lowering of the melting point and viscosity of intrinsically solid Pc2 Lu compounds has been achieved through the attachment of flexible, bulky, and long branched-alkyl chains, that is, thio-2-octyldodecyl, to the periphery of the Pc2 Lu unit. The embedded Pc2 Lu unit maintains its inherent molecular functions, such as spin-active nature and electrochromic behavior in the liquid state. Comparison of the properties with a solid-like Pc2 Lu derivative, functionalized with shorter alkyl chains, that is, thio-2-ethylhexyl, underlines the importance of the hampering effect on the π-π interactions of neighboring Pc2 Lu molecules by bulkier and longer branched-alkyl chains. This study could possibly pave the way for novel multifunctional liquids whose spin-activities are associated with their rheological or optoelectronic properties.

A glucose biosensor based on novel Lutetium bis-phthalocyanine incorporated silica-polyaniline conducting nanobeads

The facile preparation of highly sensitive electrochemical bioprobe based on lutetium phthalocyanine incorporated silica nanoparticles (SiO2(LuPc2)) grafted with Poly(vinyl alcohol-vinyl acetate) itaconic acid (PANI(PVIA)) doped polyaniline conducting nanobeads (SiO2(LuPc2)PANI(PVIA)-CNB) is reported. The preparation of CNB involves two stages (i) pristine synthesis of LuPc2 incorporated SiO2 and PANI(PVIA); (ii) covalent grafting of PANI(PVIA) onto the surface of SiO2(LuPc2). The morphology and other physico-chemical characteristics of CNB were investigated. The scanning electron microscopy images show that the average particle size of SiO2(LuPc2)PANI(PVIA)-CNB was between 180–220nm. The amperometric measurements showed that the fabricated SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor exhibited wide linear range (1–16mM) detection of glucose with a low detection limit of 0.1mM. SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor exhibited high sensitivity (38.53µAmM−1cm−2) towards the detection of glucose under optimized conditions. Besides, the real (juice and serum) sample analysis based on a standard addition method and direct detection method showed high precision for measuring glucose at SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor. The SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor stored under refrigerated condition over a period of 45 days retains ~ 96.4% glucose response current.

A novel lutetium(III) acetate phthalocyanine directly substituted with N,N’-dimethylaminophenyl groups via C[formula omitted]C bonds and its water-soluble derivative for photodynamic therapy

In this study, the novel 4-(N,N′-dimethylamino)phenyl substituted lutetium(III) acetate phthalocyanine (2) and its quaternized derivative (3) were synthesized via a Suzuki-Miyaura coupling reaction between tetrakis(iodo) lutetium(III)acetate phthalocyanine (1) and 4-(N,N-dimethylamino)phenylboronic acid, and subsequent quaternization using dimethyl sulfate, respectively. The obtained phthalocyanine 3 exhibited excellent solubility in water which is important for photodynamic therapy applications. Photophysical properties such as fluorescence quantum yield and fluorescence lifetime, and photochemical properties such as singlet oxygen generation and photostability were investigated to determine their suitability for photodynamic therapy. The lutetium(III) phthalocyanines, especially quaternized derivative 3, showed promising properties as potential photosensitizers for the treatment of cancer, producing higher singlet oxygen (ΦΔ=0.59) than motexafin lutetium (ΦΔ=0.31) which is a clinically used lutetium texaphyrin photosensitizer.

A Novel Glucose Sensor Using Lutetium Phthalocyanine as Redox Mediator in Reduced Graphene Oxide Conducting Polymer Multifunctional Hydrogel

Herein, we report a scalable synthesis of multifunctional conducting polyacrylic acid (PAA) hydrogel (MFH) integrated with reduced grapheme oxide (rGO), vinyl substituted polyaniline (VS-PANI) and lutetium phthalocyanine (LuPc2) as three dimensional robust matrix for glucose oxidase (GOx) immobilization (PAA-rGO/VS-PANI/LuPc2/GOx-MFH). We have integrated the multicomponents such as PAA with rGO, VS-PANI through free radical polymerization using methylene bis-acrylamide, ammonium persulphate as the cross linker and initiator. The LuPc2 was then doped to form multifunctional hydrogel (PAA-rGO/VS-PANI/LuPc2-MFH). Finally, biosensor was fabricated by immobilizing GOx into PAA-rGO/VS-PANI/LuPc2-MFH and subsequently used for electrochemical detection of glucose.

A novel glucose sensor using lutetium phthalocyanine as redox mediator in reduced graphene oxide conducting polymer multifunctional hydrogel

Herein, we report a scalable synthesis of multifunctional conducting polyacrylic acid (PAA) hydrogel (MFH) integrated with reduced grapheme oxide (rGO), vinyl substituted polyaniline (VS-PANI) and lutetium Phthalocyanine (LuPc2) as three dimensional robust matrix for glucose oxidase (GOx) immobilization (PAA-rGO/VS-PANI/LuPc2/GOx-MFH). We have integrated the multicomponents such as PAA with rGO, and VS-PANI through free radical polymerization using methylene bis-acrylamide, and ammonium persulphate as the cross linker and initiator. The LuPc2 was then doped to form multifunctional hydrogel (PAA-rGO/VS-PANI/LuPc2-MFH). Finally, biosensor was fabricated by immobilizing GOx into PAA-rGO/VS-PANI/LuPc2-MFH and subsequently used for electrochemical detection of glucose. The PAA-rGO/VS-PANI/LuPc2/GOx-MFH biosensor exhibited high sensitivity (15.31μAmM−1cm−2) for the detection of glucose over a concentration range of 2–12mM with a low detection limit of 25µm. The PAA-rGO/VS-PANI/LuPc2-MFH biosensor showed a fast response time (1s) to the addition of glucose with high storage stability of 3 months. The real sample analysis reveals that PAA-rGO/VS-PANI/LuPc2/GOx-MFH could be effectively used as an electrochemical biosensor in industrial as well clinical diagnosis.

Mono and Double-Decker Lutetium Phthalocyanines Bearing Iodine Groups: Electrochemical and Electrochromic Properties

In this study, novel mono 1b (LuPc) and double-decker 1c (LuPc2) lutetium(III) phthalocyanine (Pc) complexes carrying iodine groups have been synthesized and their electrochemical, in-situ spectroelectrochemical, and in-situ electrocolorimetric properties were studied and compared in solution. Electrochemically produced species of 1c displayed distinct spectral and color changes. Thus, spectroelectrochemical and electrocolorimetric measurements of cast film of 1c on indium-tin oxide (ITO) glass were also performed in aqueous solution with the aim of evaluating its applicability as an electrochromic material. ITO/LuPc2 1c cast film illustrated distinct and reversible green to yellow, green to light blue and light blue to purple color changes due to the electrochemically generated anionic and cationic forms. The film showed high optical and coulombic stabilities and especially high optic contrast during the oxidation process. The response time was also found to be satisfactorily fast for the transitions between green and yellow colors. The results showed that 1c has the potential for usage as an efficient material in electrochromic devices.

Axial ligands and (acido) (phthalocyaninato) lanthanides(III) stability on examples of erbium and lutetium

The results of a spectrophotometric study of the dissociation kinetics of the coordination centre in (phthalocyaninato) erbium(III) and lutetium(II), (X)LnPc (X = Cl, Br, AcO) in ethanol in the presence of acetic acid are reported. The kinetic equations, the numerical values of reaction rate constants and dependences of the letter on the temperature were determined by the method of excessive concentrations. The stoichiometric mechanism of the complexes dissociation and the nature of the limiting elementary reaction were substantiated and the role of axial ligands in the reaction mechanism was revealed using spectral data and the quasiequilibrium principle to describe kinetic regularities. The resulting data can help in the use of erbium and lutetium phthalocyanines as precursors in the synthesis of higher stoichiometry complexes.